In orienteering there are times when it is forbidden to cross certain symbols that have been used to depict the ground on the map. This is different depending on whether the map is made according to ISOM specifications for forest orienteering or ISSprOM for sprint orienteering.
The Orienteering Australia Competition Rules cover this in section 17 of the rules.
17. Restricted areas and routes
17.1 Rules set by Orienteering Australia or the organising Association to protect the environment and any related instructions from the organiser must be strictly observed by all persons connected with the event (see Environmental Guidelines – Appendix 7).
17.2 Out-of-bounds or dangerous areas, forbidden routes, line features that must not be crossed, etc. must be marked on the map. Where they are not obvious to the competitor, they must also be marked on the ground.
Competitors must not enter, follow or cross areas, routes or features drawn with the following symbols:

17.3 Compulsory routes, crossing points and passages must be marked clearly on the map and on the ground. Competitors must follow the entire length of any marked section of their course.
In Tasmania, many of our older maps have not been updated to the latest ISSprOM specifications. Competitors need to be aware that they may be disqualified if they cross a forbidden feature. Organisers are permitted to disqualify orienteers who breach the rules on restricted areas and routes after the results of an event are finalised. Such disqualifications may be based on evidence such as split times, GPS routes, complaints from other persons. Before this provision is used, the organiser must give the orienteer right of reply (e.g. by email).